In view of their damaging effect on human health, many doctors recommend that the maximum level of nitrates in drinking water be 10mg/litre. This is in line with the limit imposed by the Environmental Protection Agency in the United States, and with France’s Agence française de sécurité sanitaire des aliments (AFSSA).

However, European Union law allows five times that level, with a Union-wide limit of 50mg/litre imposed on member states, as stipulated by the EU’s Nitrates Directive issued in 1991.